„The Henley Passport Index“. Henley & Partners Holdings Ltd (2019-yil 1-oktyabr). — „This graph shows the full Global Ranking of the 2019 Henley Passport Index. As the index uses dense ranking, in certain cases, a rank is shared by multiple countries because these countries all have the same level of visa-free or visa-on-arrival access.“. Qaraldi: 2019-yil 1-oktyabr.
